The system-under-test's Foo() method simply returns the value of the MyProperty get property call. Unfortunately, this test always fails. When debugging, it seems the get property is always returning false.

The lack of new was actually just a typo when I was writting up the question for SO, my real code wasn't missing it. My real code was a bit more complicated so I didn't bother including it. Looking for the new keyword actually made me realize my other "not relavant" code was the problem. I had stubbed out a few more methods on MyInterface which were being executed in the constructor of MySUT. I stubbed these calls out AFTER the call to new MySUT() when they needed to be setup before the constructor call. Serves me right for trying to simplify.
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Jesse WebbJan 3 '12 at 15:04